Improvement in piston-packings for printing-presses



`C. B. COTTRELL. improvement in Piston Packing for Printingl Presses4 No.125,177. PatenieeiAprii2,1872.4

I umzutnr: y 45. ma i i ya". Mm

i gttumig CALVERT B. COTTRELL, OF WESTERLY, RHODE ISLAND.l

IMPROVEMENT IN PlSTON-PACKINGS FCR PRINTINGvPRESSES.

Specification forming part of Letters Patent No. 125,177, dated April 2, 1872.

, Specification describing a new and Improved Air-Spring Mechanism for PrintingPresses, invented by GALvnaT B. Uo'r'rRELL, of Westerly, in the county of Providence and State of lthode Island.

My invention consists, first, in the peculiar construction, hereinafter described, ot elastic piston-packing for said air-spring mechanism; and, second, in the relative arrangement ot' the vacuum-valves with the said air-spring mechanism.

Figure l is a longitudinal sectional elevation ot' a part ot' a printing-press with an airspring mechanism arranged according to my improvement. Fig. 2 is a transverse section ofthe piston on the line ac x, Fig. 3. Fig. 3 is a front elevation ot' the piston. Fig. et is partly a side elevation and partly a vertical section of the vacuum-valve mechanism; and Fig. 5 is a horizontal section ot' Fig. 4. on the line y y.

Similar letters of reference indicate corresponding parts.

A is the reciprocating bed or table ot' the printingpress, which it is desirable to arrest by the action of an air-spring at each movement, and t'or which the cylinders B on the table and the pistons C on the frame are provided. For packing these pistons with an elastic rim that will be capable of yielding to such an extent that a wad ot' paper, or the thick tapes used for carrying the papers, or any similar object falling on the piston or cylinder, as often happens, so as to be wedged in the cylinder between it and the piston, will not break or burst the cylinder, nor to any material extent interfere with the operation of the machine; also to have the said rims so that they will not expand when wholly out ot' the cylinder, as they are at each movement ot' the table, so as to interfere with entering again; I propose, in the present case, to have a strong flange, l), or its equivalent, somewhat less in diameter than the disk E, attached to the front side of said disk, between which iiange and the side F ofthe cupshaped leather packing G is an annular space, H, in which I propose to arrange four, more or less, segments, I, to be held against the inner side ot' the packing F for pressing it outward by the pins K, sliding through said iiange and pressed outward by the springs L, but limited in their outwardmovement by the nuts M, which screw forward and back on said pins to change the limit of their outward movement, as required, and which collie against the liange after pressing the packing 11 out i'ar enough to pack properly with the cylinder, and are thus prevented from expanding it, so as to interfere with the enter-ing ofthe piston in the cylinder. The springs L are capable of bending inward to a considerable extent, so as to leave the packing, as above stated. I also propose, in the present case, to attach the vacuum-valve N, used with these airspring mechanisms, to allow air to flow in behind the piston when withdrawing from the cylinder to compensate for that lost by leakage, past the piston on the end of the piston, and preferably outside ofthe cro`ss-beam of the frame instead ot' placing it on the piston, as heretofore, and to make the piston-rod O hollow for the air to flow through it when the valve risesu, The attachment to the rod is made by screwing the valve case on the end ot' the piston-rod. By this plan I am enabled to arrange it to work vertically with a very simple construction, and I have better access to it for fastening it open to prevent the compression ot' the air, as it is frequently required to do to allow oi' turning the machine by hand for cleaning, repairing, Snc.; and forI so tasten ing the valve open, l provide a button, I), to be turned under the stem and hold it open after being lifted up. And in connection with the valve-case arranged in this manner, I propose to apply a pipe-connection, It, above the valve, so as to connect the compression space in the cylinder with a governor, sometimes ,used for regula-ting the pressure for dit't'erent speeds, as-in my patent October, 17, 1871.

Having thus described my invention, I claim as new, and desire to secure by Letters Patent- 1. The combination ofthe segmental rim I, dividing pins K, adjusting nuts ll/I,` lil-ange D, and springs L, with the flexible packing rim Ii, substantially as specified.

2. The arrangement of the vacuum-valve upon the iixed hollow pistonrod O of the airspring mechanism, substantially as specified.

CALVERT B. GOTTRELL.

Witnesses:

T. B. Mosman, GEO. W. MABEE. 

